1. Valence Electrons

2. Activity Fold your periodic table so that the f and d blocks are looped. Determine the number of valence electrons for each remaining group (column). Find the pattern.

3. Valence Electrons Valence electrons – Electrons in an atom’s highest- numbered energy level. e - config. for Si: 1s 2 2s 2 2p 6 3s 2 3p 2 Si has four valence electrons. 3s 2 + 3p 2 = 4 e - e - config. for C: 1s 2 2s 2 2p 2 C also has four valence electrons.

4. Valence Electrons How many valence electrons does selenium have (element 34)? e - config: 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 4 Se has 6 valence electrons.

5. Valence Electrons Shortcut You can tell how many valence electrons any atom should have by its position in the periodic table. 1 2345 6 7 8 2 variable

6. Why are the valence electrons responsible for bonding?

7. How many valence electrons are in each of the following elements: Na (sodium) Mg (Magnesium) Xe (Xenon) Br (Bromine) C (Carbon) F (Fluorine) O (Oxygen) K (Potassium)

8. Draw a picture to explain why the valence electrons are responsible for bonding between different elements. Try to use the s & p orbital shapes.

9. Octet Rule

11. How many valence electrons do each of the following elements want to lose or gain? Na (sodium) Mg (Magnesium) Xe (Xenon) Br (Bromine) C (Carbon) F (Fluorine) O (Oxygen) K (Potassium)

12. Now, estimate the reactivity of each of the following elements based on the valence electrons. Na (sodium) Mg (Magnesium) Xe (Xenon) Br (Bromine) C (Carbon) F (Fluorine) O (Oxygen) K (Potassium)

13. Lewis Dot Diagrams

14. Electron Dot Diagram – shows the valence electrons of an atom as dots. Distribute dots around atomic symbol to represent valence electrons. Should never have more than 8 dots.

15. Lewis Dot Diagrams Here are the Lewis diagrams for 8 elements, which have 1 – 8 valence electrons. LiBeB C N O F Ne

16. Draw the Lewis Dot structure for each of the following elements: Na (sodium) Mg (Magnesium) Xe (Xenon) Br (Bromine) C (Carbon) F (Fluorine) O (Oxygen) K (Potassium)

17. Periodic Trends

18. Trends Atomic radius Electronegativity Ionization Energy How are all these important for bonding to form molecules?

19. Atomic Radius Effect of # of protons. Effect of # of electrons.

21. High Electronegativity = Strongly seeks to take an electron Low Electronegativity = Readily gives an electron

22. High Electronegativity = Strongly seeks to take an electron Low Electronegativity = Readily gives an electron

23. High Electronegativity = Strongly seeks to take an electron Low Electronegativity = Readily gives an electron

24. Energy required for another atom to remove an electron.

25. ?????

27. Trends Atomic radius How is it measured Electronegativity Ionization Energy Melting Point Boiling Point Conductivity How are all these important for bonding to form molecules?

28. Predict which elements will react with other elements.